Co Culture Of Neural Stem Cells And Bone Marrow Mesenchymal Stem Cells Combined With Photosensitive Hydrogel For Spinal Cord Injury Repair

[Objective] Preparation of gelatin methacryloyl(GelMA)hydrogel biological scaffolds and identification of related physical and chemical properties.Explore the GelMA hydrogel loaded bne mesenchymal stem cells(BMSCs)to promote neural stem cells(NSCs)differentiation and the biocompatibility of scaffolds and cells.To investigate the feasibility of GelMA hydrogel-loaded cellular scaffolds for spinal cord injury repair.[Methods] BMSCs and NSCs can proliferate or differentiate into other specific cell types.These cells represent a potential treatment for SCI.Transplantation of NSCs can promote functional recovery after acute SCI in animal experiments.NSCs are a kind of pluripotent stem cells with the ability to differentiate into neurons,oligodendrocytes and astrocytes.In particular,NSCs can secrete a variety of neurotrophic factors,inhibit the deterioration of lesions,and promote axon regeneration and remyelination.However,recent studies have shown that NSCs mainly differentiate into astrocytes rather than neurons in the microenvironment of SCI.BMSCs have been reported to promote neural differentiation of NSCs and reduce astrocyte formation.In addition,3D GelMA hydrogel provides superior mechanical and functional properties for cell action,migration and differentiation.In this study,BMSCs and NSCs were encapsulated into 3D GelMA hydrogel functional scaffolds to observe the effects of co-cultured cells in different concentrations of GelMA hydrogel on the differentiation,proliferation,viability,death and migration of NSCs.In order to further investigate the effect of combined therapy on neuronal regeneration in vivo,a T8-9 SCI model was established.Functional scaffolds loaded with BMSCs and NSCs were implanted into the spinal cord of rats at the hemisection site.Frozen sections of the spinal cord were performed 8 weeks later to observe the tissue repair.[Results] In vitro experiment,the structure and mechanical properties of spinal cord were simulated by adjusting the concentration of GelMA hydrogel.The results showed that the photoencapsulated BMSCs and NSCs in 3D GelMA hydrogel showed good effects on the survival,proliferation and migration in vitro.NSCs in the co-culture group differentiated more into neurons and oligoendrocytes than into astrocytes,and this phenomenon was more obvious in the low concentration of GelMA hydrogel.At the same time,combination therapy for SCI hemisection of rats model of repairing research shows that load BMSCs and the function of the NSCs stents in rat spinal cord hemisection axon bridge is established,the linear regeneration of axons with porous structure,function of stents can significantly improve motor function recovery and the differentiation of neurons,reduce the volume of damage of the lesions and glial scar and the formation of fibrous scar,reduce inflammation reactions.[Conclusion] In conclusion,loading BMSCs and NSCs into GelMA hydrogel scaffolds demonstrates the great therapeutic potential of the system to promote axonal regeneration,and this combination is a promising SCI treatment strategy that can trigger functional regeneration of the spinal cord.